1. Field of the Invention
The present invention relates to a display, especially adjacent sub-pixels in a display having a shared drain.
2. Description of the Prior Art
Portable electronic devices such as smart phones, notebook computers and tablets, are gradually designed to integrate multiple functions to improve audio/video functions. However, the improvements of the audio/video functions may cause high power consumption. Since the power of the portable electronic device is provided by built-in battery only, the power of the portable electronic device will soon dry out due to high power consumption, causing inconvenience to users.
Thus, how to reduce the power consumption becomes an important issue. At present, displays can be driven by analog current (AC) in a frame inversion, row inversion, column inversion or dot inversion mode. In general, displays driven in the column inversion mode have better image quality. Please refer to FIGS. 1A to 1C, which show a prior art display 100 transmitting data at various periods. The display 100 comprises a source driver 120, a plurality of switches, a plurality of data lines and a plurality of pixels. The source driver 120 outputs data signals to the pixels through a plurality of three-output demultiplexers, so as to transmit data to the sub-pixels of each pixel in sequence. In the column inversion mode, sub-pixels of two adjacent columns have opposite polarities. Based on the above, the operation of the display 100 is as follows:
In the first period, as shown in FIG. 1A, the switches T1 of the pixels P1, P2 and P3 are all turned on, so that the source driver 120 can output data to the sub-pixel r1 of the pixel P1, the sub-pixel r2 of the pixel P2 and the sub-pixel r3 of the pixel P3 through the data lines s1, s2 and s3, respectively. In the period, the data output to the sub-pixel r1 of the pixel P1 and the sub-pixel r3 of the pixel P3 has a positive polarity. The data output to the sub-pixel r2 of the pixel P2 has a negative polarity.
In the second period after the first period, as shown in FIG. 1B, the switches T1 are turned off and the switches T2 are turned on. While the sub-pixels r1, r2 and r3 stores the data received in the first period, the source driver 120 outputs data to the sub-pixels g1, g2 and g3. In order to provide sub-pixels in the adjacent columns with opposite polarities, the polarities of the data outputted by the source driver 120 in the second period are inversed to the data outputted by the source driver 120 in the first period.
In the third period after the second period, as shown in FIG. 1C, the switches T2 are turned off and the switches T3 are turned on. While the sub-pixels r1, r2 and r3 stores the data received in the first period and the sub-pixels g1, g2 and g3 stores the data received in the second period, the source driver 120 outputs data to the sub-pixels b1, b2 and b3. In order to provide sub-pixels in the adjacent columns with opposite polarities, the polarities of the data outputted by the source driver 120 in the third period are inversed to the data outputted by the source driver 120 in the second period.
In view of above, in order to implement column inversion, the source driver 120 must continuously change the output polarities, consuming a lot of power. Further each column of pixels is provided with a corresponding demultiplexer, the display 100 has to allocate a big space to accommodate the great number of demultiplexers and their associated circuitry.